Generic voltage sensor

drivetrainsystems

I hope this isn't a question with an obvious answer, because I can't seem to find one.

I have an optical sensor that varies it's output between 0-10 volts.
What is the best way to configure a Mini5+ to read that sensor?
What is the best way to then get that reading?

@dc42 this sounds like something you may know off the top of your head

drivetrainsystems

I have found

M308 S0 P"io6in" Y"linear-analog" A"DNAreader" F0

maybe effectively sets up the sensor, and

M308 S0

reads the sensors value.
I'm wondering though, how can I configure the sensor to be sensitive to the voltage range of the optical reader: 0-10v?

dc42

@drivetrainsystems use a voltage divider (2 resistors) to reduce the voltage to the range 0 to 3.3V.

o_lampe

@drivetrainsystems
Also use B and C values :

Additional parameters for linear analog sensors

    Fn F0 = unfiltered (fast response), F1 = filtered (slower response, but noise reduced and ADC oversampling used to increase resolution). F1 is only available when using a port intended for thermistors, not when using a general input port.
    Bnnn The temperature or other value when the ADC output is zero
    Cnnn The temperature or other value when the ADC output is full scale

infiniteloop

@drivetrainsystems See this thread - reading-sensor-pressure-from-analog-output for details. You can skip the posts involving the "Bi-directional Level Shifter" which returns a digital signal.

drivetrainsystems

@dc42 do understand correctly that the value reported by M308 S0 in my above example (applying your voltage divider) will be a reflection of the voltage detected between the outer pins of io6in?

For instance, if I configure the reply value range for 0-100, and my sensor generates 5v (dropped to ~1.65v), will M308 S0 report a value of 50? (hope my details are sensible, I'm not quite yet grasping all the particulars of the process)

dc42

@drivetrainsystems that's correct, except that there is a 27Kohm pullup resistor to +3.3V on each IO_IN input which will affect the reading a little. It's not hard to calculate how much.

drivetrainsystems

@dc42 unfortunately my electronics skills are limited. I can put the calc in front of my electronics guy, unless you know what to do off the top of your head? iIf so, I can put your formula into the software ASAP,

dc42

@drivetrainsystems I've put a spreadsheet that you can copy to calculate it at https://docs.google.com/spreadsheets/d/1RHeHdqUFcPJ-TeWF9t5B-z-C7YzHEIGwSDQcROe8kqE/edit?usp=sharing.

drivetrainsystems

@dc42 thanks!